Fix/get method from stackframe

Harmony/Internal/CodeTranspiler.cs

@@ -194,7 +194,7 @@ internal static IEnumerable ConvertToGeneralInstructions(MethodInfo transpiler,
 		{
 			var type = transpiler.GetParameters()
 				.Select(p => p.ParameterType)
-				.FirstOrDefault(t => IsCodeInstructionsParameter(t));
+				.FirstOrDefault(IsCodeInstructionsParameter);
 			if (type == typeof(IEnumerable<CodeInstruction>))
 			{
 				unassignedValues = null;

Harmony/Internal/HarmonySharedState.cs

@@ -35,17 +35,24 @@ internal static class HarmonySharedState
 		const string name = "HarmonySharedState";
 		internal const int internalVersion = 102; // bump this if the layout of the HarmonySharedState type changes
 
-		// state/originals/methodStarts are set to instances stored in the global dynamic types static fields with the same name
+		// state/originals/originalsMono are set to instances stored in the global dynamic types static fields with the same name
 		static readonly Dictionary<MethodBase, byte[]> state;
 		static readonly Dictionary<MethodInfo, MethodBase> originals;
-
+		static readonly Dictionary<long, MethodBase[]> originalsMono;
+
+		static readonly AccessTools.FieldRef<StackFrame, long> methodAddressRef;
+
 		internal static readonly int actualVersion;
 
 		static HarmonySharedState()
 		{
 			// create singleton type
 			var type = GetOrCreateSharedStateType();
 
+			// this field is useed to find methods from stackframes in Mono
+			if (AccessTools.IsMonoRuntime && AccessTools.Field(typeof(StackFrame), "methodAddress") is FieldInfo field)
+				methodAddressRef = AccessTools.FieldRefAccess<StackFrame, long>(field);
+
 			// copy 'actualVersion' over to our fields
 			var versionField = type.GetField("version");
 			if ((int)versionField.GetValue(null) == 0)
@@ -62,13 +69,23 @@ static HarmonySharedState()
 			if (originalsField != null && originalsField.GetValue(null) is null)
 				originalsField.SetValue(null, new Dictionary<MethodInfo, MethodBase>());
 
+			// get or initialize global 'originalsMono' field
+			var originalsMonoField = type.GetField("originalsMono");
+			if (originalsMonoField != null && originalsMonoField.GetValue(null) is null)
+				originalsMonoField.SetValue(null, new Dictionary<long, MethodBase[]>());
+
 			// copy 'state' over to our fields
 			state = (Dictionary<MethodBase, byte[]>)stateField.GetValue(null);
 
 			// copy 'originals' over to our fields
 			originals = [];
 			if (originalsField != null) // may not exist in older versions
 				originals = (Dictionary<MethodInfo, MethodBase>)originalsField.GetValue(null);
+
+			// copy 'originalsMono' over to our fields
+			originalsMono = [];
+			if (originalsMonoField != null) // may not exist in older versions
+				originalsMono = (Dictionary<long, MethodBase[]>)originalsMonoField.GetValue(null);
 		}
 
 		// creates a dynamic 'global' type if it does not exist
@@ -94,6 +111,12 @@ static Type GetOrCreateSharedStateType()
 				module.ImportReference(typeof(Dictionary<MethodInfo, MethodBase>))
 			));
 
+			typedef.Fields.Add(new FieldDefinition(
+				"originalsMono",
+				Mono.Cecil.FieldAttributes.Public | Mono.Cecil.FieldAttributes.Static,
+				module.ImportReference(typeof(Dictionary<long, MethodBase[]>))
+			));
+
 			typedef.Fields.Add(new FieldDefinition(
 				"version",
 				Mono.Cecil.FieldAttributes.Public | Mono.Cecil.FieldAttributes.Static,
@@ -122,19 +145,49 @@ internal static void UpdatePatchInfo(MethodBase original, MethodInfo replacement
 		{
 			var bytes = patchInfo.Serialize();
 			lock (state) state[original] = bytes;
-			lock (originals) originals[replacement] = original;
+			lock (originals) originals[replacement.Identifiable()] = original;
+			if (AccessTools.IsMonoRuntime)
+			{
+				var methodAddress = (long)replacement.MethodHandle.GetFunctionPointer();
+				lock (originalsMono) originalsMono[methodAddress] = [original, replacement];
+			}
 		}
 
-		internal static MethodBase GetOriginal(MethodInfo replacement)
+		// With mono, useReplacement is used to either return the original or the replacement
+		// On .NET, useReplacement is ignored and the original is always returned
+		internal static MethodBase GetRealMethod(MethodInfo method, bool useReplacement)
 		{
-			lock (originals) return originals.GetValueSafe(replacement);
+			var identifiableMethod = method.Identifiable();
+			lock (originals)
+				if (originals.TryGetValue(identifiableMethod, out var original))
+					return original;
+
+			if (AccessTools.IsMonoRuntime)
+			{
+				var methodAddress = (long)method.MethodHandle.GetFunctionPointer();
+				lock (originalsMono)
+					if (originalsMono.TryGetValue(methodAddress, out var info))
+						return useReplacement ? info[1] : info[0];
+			}
+
+			return method;
 		}
 
-		internal static MethodBase FindReplacement(StackFrame frame)
+		internal static MethodBase GetStackFrameMethod(StackFrame frame, bool useReplacement)
 		{
 			var method = frame.GetMethod() as MethodInfo;
-			if (method == null) return null;
-			return GetOriginal(method);
+			if (method != null)
+				return GetRealMethod(method, useReplacement);
+
+			if (methodAddressRef != null)
+			{
+				var methodAddress = methodAddressRef(frame);
+				lock (originalsMono)
+					if (originalsMono.TryGetValue(methodAddress, out var info))
+						return useReplacement ? info[1] : info[0];
+			}
+
+			return null;
 		}
 	}
 }

Harmony/Internal/MethodCopier.cs

@@ -358,7 +358,7 @@ internal List<CodeInstruction> FinalizeILCodes(Emitter emitter, List<MethodInfo>
 			// pass2 - filter through all processors
 			//
 			var codeTranspiler = new CodeTranspiler(ilInstructions);
-			transpilers.Do(transpiler => codeTranspiler.Add(transpiler));
+			transpilers.Do(codeTranspiler.Add);
 			var codeInstructions = codeTranspiler.GetResult(generator, method);
 
 			if (emitter is null)

Harmony/Internal/MethodPatcher.cs

@@ -101,7 +101,7 @@ internal MethodInfo CreateReplacement(out Dictionary<int, CodeInstruction> final
 
 			Label? skipOriginalLabel = null;
 			LocalBuilder runOriginalVariable = null;
-			var prefixAffectsOriginal = prefixes.Any(fix => PrefixAffectsOriginal(fix));
+			var prefixAffectsOriginal = prefixes.Any(PrefixAffectsOriginal);
 			var anyFixHasRunOriginalVar = fixes.Any(fix => fix.GetParameters().Any(p => p.Name == RUN_ORIGINAL_VAR));
 			if (prefixAffectsOriginal || anyFixHasRunOriginalVar)
 			{

Harmony/Internal/PatchModels.cs

@@ -101,7 +101,7 @@ internal static AttributePatch Create(MethodInfo patch)
 					var f_info = AccessTools.Field(attr.GetType(), nameof(HarmonyAttribute.info));
 					return f_info.GetValue(attr);
 				})
-				.Select(harmonyInfo => AccessTools.MakeDeepCopy<HarmonyMethod>(harmonyInfo))
+				.Select(AccessTools.MakeDeepCopy<HarmonyMethod>)
 				.ToList();
 			var info = HarmonyMethod.Merge(list);
 			info.method = patch;

Harmony/Internal/PatchTools.cs

@@ -32,7 +32,7 @@ internal static void DetourMethod(MethodBase method, MethodBase replacement)
 		static Assembly GetExecutingAssemblyReplacement()
 		{
 			var frames = new StackTrace().GetFrames();
-			if (frames?.Skip(1).FirstOrDefault() is { } frame && Harmony.GetOriginalMethodFromStackframe(frame) is { } original)
+			if (frames?.Skip(1).FirstOrDefault() is { } frame && Harmony.GetMethodFromStackframe(frame) is { } original)
 				return original.Module.Assembly;
 			return Assembly.GetExecutingAssembly();
 		}
@@ -78,7 +78,7 @@ internal static AssemblyBuilder DefineDynamicAssembly(string name)
 		internal static List<AttributePatch> GetPatchMethods(Type type)
 		{
 			return AccessTools.GetDeclaredMethods(type)
-				.Select(method => AttributePatch.Create(method))
+				.Select(AttributePatch.Create)
 				.Where(attributePatch => attributePatch is not null)
 				.ToList();
 		}

Harmony/Public/Harmony.cs

@@ -1,4 +1,3 @@
-using MonoMod.Core.Platforms;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -227,7 +226,7 @@ public void Unpatch(MethodBase original, MethodInfo patch)
 		public static bool HasAnyPatches(string harmonyID)
 		{
 			return GetAllPatchedMethods()
-				.Select(original => GetPatchInfo(original))
+				.Select(GetPatchInfo)
 				.Any(info => info.Owners.Contains(harmonyID));
 		}
 
@@ -252,15 +251,13 @@ public IEnumerable<MethodBase> GetPatchedMethods()
 		public static IEnumerable<MethodBase> GetAllPatchedMethods() => PatchProcessor.GetAllPatchedMethods();
 
 		/// <summary>Gets the original method from a given replacement method</summary>
-		/// <param name="replacement">A replacement method, for example from a stacktrace</param>
+		/// <param name="replacement">A replacement method (patched original method)</param>
 		/// <returns>The original method/constructor or <c>null</c> if not found</returns>
 		///
 		public static MethodBase GetOriginalMethod(MethodInfo replacement)
 		{
 			if (replacement == null) throw new ArgumentNullException(nameof(replacement));
-			// The runtime can return several different MethodInfo's that point to the same method. Use the correct one
-			var identifiableReplacement = PlatformTriple.Current.GetIdentifiable(replacement) as MethodInfo;
-			return HarmonySharedState.GetOriginal(identifiableReplacement);
+			return HarmonySharedState.GetRealMethod(replacement, useReplacement: false);
 		}
 
 		/// <summary>Tries to get the method from a stackframe including dynamic replacement methods</summary>
@@ -270,24 +267,23 @@ public static MethodBase GetOriginalMethod(MethodInfo replacement)
 		public static MethodBase GetMethodFromStackframe(StackFrame frame)
 		{
 			if (frame == null) throw new ArgumentNullException(nameof(frame));
-			return HarmonySharedState.FindReplacement(frame) ?? frame.GetMethod();
+			return HarmonySharedState.GetStackFrameMethod(frame, useReplacement: true);
 		}
 
 		/// <summary>Gets the original method from the stackframe and uses original if method is a dynamic replacement</summary>
 		/// <param name="frame">The <see cref="StackFrame"/></param>
 		/// <returns>The original method from that stackframe</returns>
 		public static MethodBase GetOriginalMethodFromStackframe(StackFrame frame)
 		{
-			var member = GetMethodFromStackframe(frame);
-			if (member is MethodInfo methodInfo)
-				member = GetOriginalMethod(methodInfo) ?? member;
-			return member;
+			if (frame == null) throw new ArgumentNullException(nameof(frame));
+			return HarmonySharedState.GetStackFrameMethod(frame, useReplacement: false);
 		}
 
 		/// <summary>Gets Harmony version for all active Harmony instances</summary>
 		/// <param name="currentVersion">[out] The current Harmony version</param>
 		/// <returns>A dictionary containing assembly versions keyed by Harmony IDs</returns>
 		///
-		public static Dictionary<string, Version> VersionInfo(out Version currentVersion) => PatchProcessor.VersionInfo(out currentVersion);
+		public static Dictionary<string, Version> VersionInfo(out Version currentVersion)
+			=> PatchProcessor.VersionInfo(out currentVersion);
 	}
 }

Harmony/Public/HarmonyMethod.cs

@@ -292,7 +292,7 @@ static HarmonyMethod GetHarmonyMethodInfo(object attribute)
 		public static List<HarmonyMethod> GetFromType(Type type)
 		{
 			return type.GetCustomAttributes(true)
-						.Select(attr => GetHarmonyMethodInfo(attr))
+						.Select(GetHarmonyMethodInfo)
 						.Where(info => info is not null)
 						.ToList();
 		}
@@ -310,7 +310,7 @@ public static List<HarmonyMethod> GetFromType(Type type)
 		public static List<HarmonyMethod> GetFromMethod(MethodBase method)
 		{
 			return method.GetCustomAttributes(true)
-						.Select(attr => GetHarmonyMethodInfo(attr))
+						.Select(GetHarmonyMethodInfo)
 						.Where(info => info is not null)
 						.ToList();
 		}

Harmony/Tools/AccessTools.cs

@@ -1,3 +1,4 @@
+using MonoMod.Core.Platforms;
 using MonoMod.Utils;
 using System;
 using System.Collections;
@@ -84,7 +85,7 @@ public static Type[] GetTypesFromAssembly(Assembly assembly)
 		/// <summary>Enumerates all successfully loaded types in the current app domain, excluding visual studio assemblies</summary>
 		/// <returns>An enumeration of all <see cref="Type"/> in all assemblies, excluding visual studio assemblies</returns>
 		///
-		public static IEnumerable<Type> AllTypes() => AllAssemblies().SelectMany(a => GetTypesFromAssembly(a));
+		public static IEnumerable<Type> AllTypes() => AllAssemblies().SelectMany(GetTypesFromAssembly);
 
 		/// <summary>Enumerates all inner types (non-recursive) of a given type</summary>
 		/// <param name="type">The class/type to start with</param>
@@ -133,6 +134,11 @@ public static T FindIncludingInnerTypes<T>(Type type, Func<Type, T> func) where
 			return result;
 		}
 
+		/// <summary>Creates an identifiable version of a method</summary>
+		/// <param name="method">The method</param>
+		/// <returns></returns>
+		public static MethodInfo Identifiable(this MethodInfo method) => PlatformTriple.Current.GetIdentifiable(method) as MethodInfo ?? method;
+
 		/// <summary>Gets the reflection information for a directly declared field</summary>
 		/// <param name="type">The class/type where the field is defined</param>
 		/// <param name="name">The name of the field</param>

HarmonyTests/Extras/RetrieveOriginalMethod.cs

@@ -3,6 +3,7 @@
 using System;
 using System.Diagnostics;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
 namespace HarmonyLibTests.Extras
 {
@@ -14,20 +15,20 @@ private static void CheckStackTraceFor(MethodBase expectedMethod)
 			Assert.NotNull(expectedMethod);
 
 			var st = new StackTrace(1, false);
-			var method = Harmony.GetMethodFromStackframe(st.GetFrame(0));
-
-			Assert.NotNull(method);
-
-			if (method is MethodInfo replacement)
-			{
-				var original = Harmony.GetOriginalMethod(replacement);
-				Assert.NotNull(original);
-				Assert.AreEqual(original, expectedMethod);
-			}
+			var frame = st.GetFrame(0);
+			Assert.NotNull(frame);
+
+			var methodFromStackframe = Harmony.GetMethodFromStackframe(frame);
+			Assert.NotNull(methodFromStackframe);
+			Assert.AreEqual(expectedMethod, methodFromStackframe);
+
+			var replacement = frame.GetMethod() as MethodInfo;
+			Assert.NotNull(replacement);
+			var original = Harmony.GetOriginalMethod(replacement);
+			Assert.NotNull(original);
+			Assert.AreEqual(expectedMethod, original);
 		}
 
-		/* TODO
-		 * 
 		[Test]
 		public void TestRegularMethod()
 		{
@@ -37,7 +38,7 @@ public void TestRegularMethod()
 			_ = harmony.Patch(originalMethod, new HarmonyMethod(dummyPrefix));
 			PatchTarget();
 		}
-		
+
 		[Test]
 		public void TestConstructor()
 		{
@@ -48,7 +49,6 @@ public void TestConstructor()
 			var inst = new NestedClass(5);
 			_ = inst.index;
 		}
-		*/
 
 		internal static void PatchTarget()
 		{
@@ -60,7 +60,7 @@ internal static void PatchTarget()
 			}
 		}
 
-		// [MethodImpl(MethodImplOptions.NoInlining)]
+		[MethodImpl(MethodImplOptions.NoInlining)]
 		internal static void DummyPrefix()
 		{
 		}
@@ -69,7 +69,7 @@ class NestedClass {
 			public NestedClass(int i)
 			{
 				try {
-					CheckStackTraceFor(AccessTools.Constructor(typeof(NestedClass), [typeof(int)])); 
+					CheckStackTraceFor(AccessTools.Constructor(typeof(NestedClass), [typeof(int)]));
 					throw new Exception();
 				} catch (Exception e)
 				{